We present a rare manifestation of chronic lymphatic leukemia with progressive bilateral visual loss and the typical fundoscopic picture of anterior ischemic optic nerve neuropathy (AION). Clinical symptoms were due to meningeal metastases and tumor cell infiltration of the optic nerve. The diagnostic clue was provided by lumbar puncture with pressure measurement, which made it possible to differentiate AION from papillitis and papilledema. In this case the patient was able to regain his initial visual activity after intrathecal and systemic polychemotherapy.